Fiber optic ferrule polishing device

ABSTRACT

A fiber optic ferrule polishing devise comprising a disk having an outer periphery and a center. Rings having a polishing surface coated with varying degrees of abrasive and attached to the disk such that the courseness of abrasive on the rings decreases from the outer periphery to the center. A ferrule holder having a ferrule holding recess adjacent to the polishing surface, a water injecting recess and an attachment arm pivotally attached to the ferrule holder such that the arm is positioned adjacent to the ferrule holding recess. A holding plate having a ferrule end face receiving recess having a smaller diameter than the ferrule holding recess and positioned adjacent to the ferrule holding recess and polishing surface. A mounting plate for mounting the ferrule holder a predetermined distance from the polishing surface. The arm biases a ferrule toward the polishing surface when a ferrule is received in the ferrule holding recess.

FIELD OF THE INVENTION

[0001] The invention relates to a polishing device and, more particularly, to a device for polishing fiber optic ferrules.

BACKGROUND OF THE INVENTION

[0002] Fiber optic connectors typically consist of a ferrule having a fiber optic cable comprising an optical fiber encompassed by a buffer extending therethrough. The ferrule has a substantially flat end face through which projecting segments of the optical fiber are inserted and bonded by an adhesive. To prepare the ferrule for connection, the projecting segments of the optical fiber are polished flush with the surface of the end face of the ferrule. First, the surface of the end face is rough polished to remove the projecting segments. Then, the surface of the end face is final polished to remove processing strain layers or any other surface irregularities.

[0003] Because the polishing is required to be done with high precision in order to insure an optimal optical connection between two abutting end face surfaces, it is known to secure the ferrule in a fixture and position the end face against a grinding or polishing wheel. One such ferrule polishing device is disclosed in U.S. Pat. No. 5,503,590 issued to Saitoh et al. Saitoh et al. teaches an elastic film polishing plate for a fiber optic connector having an adhesive removing ring area along an outer area of a polishing wheel. A rough polishing ring area is disposed inward of the adhesive removing ring area, and a final polishing ring area is located concentrically on the polishing wheel. Each of the ring areas is formed of an elastic film to which an abrasive liquid is applied during rotation. The abrasive liquid is varied in each section in order to achieve either a rough or fine polishing. A plurality of partition rings are each disposed between the each ring section to prevent the abrasive liquids from mixing with each other. This device requires the injection of several abrasive liquids and containment of these various abrasives over various ring areas to achieve either the rough or final polishing desired at that specific ring area. These abrasive liquids are costly and the consumables of the process further add to process costs. Further, this device does not have a continuos abrasive surface to allow a single pass polishing of the end face.

[0004] It is therefore desirable to develop a fiber optic ferrule polishing device that is less intricate reduces the consumables cost and has a continuous abrasion surface to allow single pass polishing of a ferrule end face and efficient manufacturing of the ferrule.

SUMMARY OF THE INVENTION

[0005] The invention relates to a fiber optic ferrule polishing devise comprising a disk, a plurality of rings and a ferrule holder. The disk having an outer periphery and a center. The plurality of rings each having a polishing surface coated with varying degrees of abrasive and an attachment surface. The attachment surface is attached to the disk such that the courseness of abrasive on the rings decreases from the outer periphery to the center. The ferrule holder has a ferrule holding recess substantially adjacent to the polishing surface and an attachment arm pivotally attached to the ferrule holder such that the arm is positioned substantially adjacent to the ferrule holding recess. The attachment arm biases the fiber optic ferrule toward the disk polishing surface when a fiber optic ferrule is received in the ferrule holding recess.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The invention will now be described by way of example with reference to the accompanying figures in which:

[0007]FIG. 1 is an isometric view of the fiber optic ferrule polishing device.

[0008]FIG. 2 is a schematic view of the attachment of the rings to the disk.

[0009]FIG. 3 is a partially-sectioned exploded view of the rings attached to the disk taken along line 3-3 in FIG. 1.

[0010]FIG. 4 is a partial isometric view of the ferrule holder and the rings.

[0011]FIG. 5 is a top cross-sectional view of the fixture assembly taken along line 5-5 in FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0012]FIG. 1 shows a fiber optic ferrule polishing device 10 comprising a polishing assembly 20 and a fixture assembly 60 attached to a base 12. The polishing assembly 20 comprises an axially preloaded spindle motor 22 having a spindle 30 extending therefrom that is received in a hub 36. The hub 36 has an attached polishing surface 52 comprising a plurality of rings 50. A shroud 210 is positioned about the hub 36 and the attached polishing surface 52. The fixture assembly 60 comprises a fiber optic ferrule holder 100 attached to a mounting plate 212 that is attached to a mounting structure 76. The ferrule holder 100 has a water injecting recess 102, a ferrule holding recess 105 and an attached holding arm 226. The mounting structure 76 is moveably mounted on a slide base 62 and has a threaded shaft 78 extending therefrom that is received in a motor 80. Alternatively, a linear slide motor assembly may be used instead of the threaded shaft 78 and motor 80.

[0013] The main components of the fiber optic ferrule polishing device 10 will now be described in greater detail beginning with the polishing assembly 20 as shown in FIGS. 1 through 3. Referring to FIG. 1, the axially preloaded spindle motor 22 is contained in a housing 24. A supporting structure 32 extends from a bottom surface 34 of the housing 24 and is attached to a top surface 14 of the base 12. A first end 26 of the spindle 30 extends substantially parallel to the base 12 from a front surface 90 of the housing 24. A second end 28 of the spindle 30 is received in the hub 36.

[0014] Shown in FIGS. 2 and 3, the hub 36 is made out of a material such as steel, aluminum, or other materials having similar properties and comprises a mating portion 38 and a disk 40. The mating portion 38 is substantially cylindrical in shape and is dimensioned for receipt of the second end 28 of the spindle 30. The disk 40 has a front side 42 and a back side 44. A plurality of securing apertures 46 extends through the disk 40 from the front side 42 to the back side 44. The securing apertures 46 are positioned radially from the disk center 92 to the disk outer periphery 94. Attached to the front side 42 of the disk is a plurality of rings 50. Each ring 50 is preferably made out of a magnetic material such as steel and has an attachment surface 54 and a polishing surface 52. A magnetic material facilitates manufacturing in that the rings 50 can be magnetically retained during a grinding operation. The attachment surface 54 has a plurality of threaded ring apertures 56 that correspond to the securing apertures 46 on the back side 44 of the disk 40. The ring apertures 56 are positioned on the attachment surface 54 and do not extend through to the polishing surface 52 of the rings 50. Each ring 50 is formed to slip fit into each other. Cap screws 16 or other suitable fastening means are positioned in the securing apertures 46 on the back side 44 of the disk 40. The cap screws 16 extend through the front side 42 of the disk 40 and are received into the threaded ring apertures 56 of the attachment surface 54.

[0015] The polishing surface 52 of each of the rings 50 is coated with diamond grit 58 or other suitable abrasive such as man made diamond grit, ceramic, or carborundum. The diamond grit 58 or other suitable abrasive has a different size and number of particles disposed per unit area on each ring 50. The ring 50 located at the disk outer periphery 94 is coated with the coarsest abrasive. Moving inward from the disk outer periphery 94 toward the disk center 92, each ring is progressively less coarse and protrudes further outward from the hub 36 wherein the ring located at the disk center 92 is coated with the finest abrasive and protrudes farthest from the hub 36.

[0016] As shown in FIG. 1, the shroud 210 has a shroud first side 220, a shroud second 218 side, a shroud top 222 and a shroud bottom 224. The shroud bottom 224 is positioned adjacent to the top surface 14 of the base 12. The shroud first side 220 is positioned substantially parallel to the polishing surface 52. The shroud first side 220 has a slot 110 that extends substantially parallel and adjacent to the polishing surface 52 from substantially near the disk outer periphery 92 to substantially near the disk center 94. The shroud second side 218 is positioned substantially parallel to the disk 40. The shroud second side 218 has an opening (not shown) substantially adjacent to the mating portion 38 of the hub 36. It will be appreciated by those skilled in the art that the shroud 210 can take a variety of shapes and forms to achieve a substantially similar result.

[0017] The main components of the fixture assembly 60 will now be described in greater detail with reference to FIGS. 1, 4 and 5. Shown in FIG. 1, the slide base 62 is a substantially flat elongated member having a plate top surface 64, a plate bottom surface 66, and first and second plate ends 68, 70, respectively. The plate bottom surface 66 is positioned adjacent to and is attached to the top surface 14 of the base 12. A first plate wall 72 extends substantially perpendicular and adjacent to the first plate end 68. A second plate wall 74 extends substantially perpendicular and adjacent to the second plate end 70.

[0018] Positioned adjacent to the plate top surface 64 is the mounting structure 76. The mounting structure 76 is substantially rectangular in shape and has a mounting structure bottom surface 88, and a mounting structure top surface 84. The mounting structure bottom surface 88 is attached to the plate top surface 64. A first portion 82 of a threaded shaft 78 extends through a side 98 of the mounting structure 76 and is positioned substantially parallel to the slide base 62. A second portion 86 of the threaded shaft 78 extends through a wall aperture (not shown) in the second plate wall 74 and is received in a motor 80.

[0019] Positioned adjacent to the mounting structure 76 is the mounting plate 212. As shown in FIG. 4, the mounting plate 212 is substantially rectangular in shape and has a mounting plate top surface 214 and a mounting plate bottom surface 216. The mounting plate bottom surface 216 is attached to the mounting structure top surface 84. The mounting plate top surface 21 has mounting plate apertures (not shown). The mounting plate 212 is movable toward and away from the polishing surface 52 by a threaded shaft 97 extending therethough. The threaded shaft is optionally driven by a motor 96 or manually driven. A positional indicator 99 is provided to indicate travel in the direction toward and away from the polishing surface 52.

[0020] Positioned adjacent to the mounting plate 212 is a ferrule holder 100. As shown in FIG. 4, the ferrule holder 100 has a polishing end 103, a receiving end 105, a holder top surface 106, a holder bottom surface 108, and holder first and second sides, 118, 120, respectively. The holder bottom surface 108 is positioned adjacent to the mounting plate top surface 214. The polishing end 103 of the ferrule holder 100 extends beyond the mounting plate top surface 214 and is positioned substantially adjacent to the polishing surface 52 of the rings 50. The receiving end 104 of the ferrule holder 100 has an attachment member 109. The attachment member has an attachment member aperture (not shown). A bolt 112 or other suitable fastening means extends through the attachment member aperture and into the mounting plate aperture (not shown).

[0021] Substantially near the holder top surface 106 is a ferrule holding recess 105. As shown in FIG. 5, the ferrule holding recess 105 is positioned toward the holder first side 118 and extends from the polishing end 103 through to the receiving end 105 of the ferrule holder 100. Substantially near the holder top surface 106 is also a water injecting recess 102. The water injecting recess 102 is positioned toward the holder second side 120 and has a first portion 114 and a second portion 116. The first portion 114 extends substantially parallel to the ferrule holding recess 105 from the polishing end 103 to substantially near the receiving end 105. The second portion 116 extends substantially perpendicular to the ferrule holding recess 105 from the end of the first portion 114 substantially near the receiving end 114 to the holder second side 120. Ferrule holder apertures 124 extend substantially parallel to and flank the water injecting recess 102 and the ferrule holding recess 105. It will be appreciated by those skilled in the art that while the water injecting recess 102 is positioned toward the holder second side 120 and the ferrule holding recess 105 is positioned toward the holder first side 118, the positions may be interchanged or varied to achieve substantially similar results.

[0022] As shown in FIGS. 4 and 5, a holding plate 122 is positioned adjacent to the polishing end 103 of the ferrule holder 100. The holding plate 122 has a holding plate first side 125 positioned adjacent to the polishing end 103 and a holding plate second side 127 positioned substantially parallel to the polishing surface 52. The holding plate 122 has a ferrule end face receiving recess 126 extending from the holding plate first side 125 through to the holding plate second side 127. The ferrule end face receiving recess 126 has a slightly smaller diameter than the ferrule holding recess 105 and is positioned adjacent to the ferrule holding recess 105. A water ejecting recess 128 is positioned substantially parallel to the ferrule end face holding recess 126 and extends from the holding plate first side 125 through to the holding plate second side 127. The water ejecting recess 128 is positioned adjacent to the first portion 114 of the water injecting recess 102. Holding plate apertures 130 flank the ferrule end face receiving recess 126 and the water ejecting recess 128 and are positioned adjacent to the ferrule holder apertures 124. Bolts 132 or other suitable fastening means extend from the holding plate first side 125 through the holding plate apertures 130 and into the ferrule holder apertures 124.

[0023] As shown in FIG. 4, a holding arm 226 is positioned adjacent to the holder top surface 106 substantially above the ferrule holding recess 105 and substantially near the holder first side 118. The holding arm 226 has an arm 140 and first and second arm mounts 148, 150, respectively. The first arm mount 148 and second arm mount 150 are positioned substantially perpendicular to the holder top surface 106 and substantially parallel to each other. A spring 228 extends substantially perpendicular to and between the first and second arm mounts 148, 150.

[0024] The arm 140 has a first flange 134 and a second flange 136 positioned at an arm top end 139. The first flange 134 is positioned toward the holder first side 118 and extends adjacent to the first arm mount 148. A first tip end 147 of the first flange 134 is pivotally attached to the first arm mount 148. The second flange 136 is positioned toward the holder second side 120 and extends adjacent to the second arm mount 150. A second tip end 146 of the second flange 136 is pivotally attached to the second arm mount 150. Substantially centered at an arm bottom end 138 is a cable receiving recess 132. The cable receiving recess 132 is positioned substantially parallel to the ferrule holding recess 1S and extends from the arm bottom end 138 toward the arm top end 139 to form first and second legs 230, 232, respectively.

[0025]FIG. 5 shows a fiber optic cable connector 200 comprising a fiber optic cable 152 and a ferrule assembly 154. The fiber optic cable 152 has a central optical fiber 202 that is surrounded by a buffer 204 encompassed with a flexible jacket 206. The ferrule assembly 154 comprises a ferrule 160 having an outer surface 172 and an inner surface 174. Moving from the front end 156 of the ferrule assembly 154 toward the rear end 158, the ferrule 160 has a first section 162 having an end face 164. Adjacent the first section 162 of the ferrule 160 and opposite of the end face 164 is a second section 166. The second section 166 has a shoulder 168 having a diameter slightly larger than the diameter of the first section 162. The outer surface 172 of the second section 166 has a plurality of raised portions 170 and recessed portions 176. Adjacent the second section 166 of the ferrule 160 and opposite of the shoulder 168 is a first holding portion 178. The first holding portion 178 has first holding portion first and second flanges 180, 182 that extend from a first base portion 184 and substantially converge adjacent to the second section 166. Adjacent the first holding portion 178 is a second holding portion 186. The second holding portion 186 has second holding portion first and second flanges 188, 190 that extend from a second base portion 192 and substantially converge adjacent to the first base portion 184. Adjacent the second base portion 192 is a resilient ferrule spring 194. The fiber optic cable 152 is disposed in the ferrule assembly 154 such that a projecting segment 208 of the optical fiber 202 projects from the ferrule 160 end face 164.

[0026] The method of polishing the ferrule 160 end face 164 of the fiber optic cable end connector 200 will now be described in greater detail. First, the fiber optic cable connector 200 is positioned in the ferrule holding recess 105 by pivoting the holding arm 226 away from the ferrule holding recess 105. The ferrule 160 end face 164 is received in the ferrule holder 100 ferrule holding recess 105. The end face 164 is inserted into the ferrule holding recess 105 until it is received in the ferrule end face receiving recess 126 and projects from the holding plate second side 127. The holding arm 226 is then pivoted to its initial position adjacent to the ferrule holder 100 receiving end 104. The fiber optic cable 152 is received in the cable receiving recess 132 between the first and second legs 230, 232. The resiliency of the spring 228 biases the legs 230, 232 toward the receiving end 104 and against the ferrule spring 194 projecting from the ferrule receiving recess 105. The ferrule spring 194 then biases the fiber optic cable connector 150 toward the holding plate second side 127 until the shoulder 168 of the ferrule 160 engages to the holding plate first side 125.

[0027] As shown in FIG. 1, the fixture assembly 60 is positioned substantially adjacent to the disk outer periphery 94 such that the end face 164 and the projecting segment 208 of the optical fiber 202 are positioned within the slot 110. The fixture assembly 60 is then moved toward the polishing surface 52 by the motor 96 and shaft 97 operating on the mounting plate 212 such that the fiber end face and ferrule contact the polishing surface 52. The positional indicator 99 is used to determine the amount of material which is to be removed from the ferrule and fiber end face. While the disk 16 spins and water is injected through the water injecting recess 102, the motor 80 drives the threaded shaft 78 causing the mounting structure 76 to move adjacent to the plate top surface 64 and parallel to the polishing surface 52 from the disk outer periphery 94 to the disk center 92. It should be noted here that water having a pH between 7 and 8 exhibits favorable results in that it acts as a wetting agent without unduly etching the glass of the fiber end being polishing. Additionally, soap and anti-foaming agents may be added to the water to keep the polishing surface 52 clear of material which was removed from the ferrule and fiber end face. As the mounting structure 76 travels from the disk outer periphery 94 to the disk center 92, the end face 164 and projecting segment 208 contact the rotating polishing surface 52 of the ring 50 positioned at the disk outer periphery 94 having the coarsest abrasive. As the end face 164 continues to move toward the disk center 92, the end face 164 moves toward the finest ring 50 to achieve a finely polished fiber optic ferrule 160 end face 164 in a single pass polishing.

[0028] Further, as the mounting structure 76 travels from the disk outer periphery 94 to the disk center 92, water or other cleaner or lubricant is injected through water infeed tubing (not shown), through the water injecting recess 102 and is expelled from the water ejecting recess 128 onto the polishing surface 52 of the rings 50 to remove debris and/or lubricate the polishing surface 52 subsequent to the ferrule 160 end face 164 contacting the polishing surface 52. Excess water and debris is, thereby, contained in the shroud 222 and drained through the base 12 utilizing well known techniques.

[0029] The foregoing illustrates some of the possibilities for practicing the invention. Many other embodiments are possible within the scope and spirit of the invention. It is, therefore, intended that the foregoing description be regarded as illustrative rather than limiting, and that the scope of the invention is given by the appended claims together with their full range of equivalents. 

What is claimed is:
 1. A fiber optic ferrule polishing devise comprising: a disk having an outer periphery and a center; a plurality of rings having a polishing surface coated with varying degrees of abrasive and an attachment surface attached to the disk such that the courseness of abrasive on the rings decreases from the outer periphery to the center; a ferrule holder having a ferrule holding recess substantially adjacent to the polishing surface and an attachment arm pivotally attached to the ferrule holder such that the arm is positioned substantially adjacent to the ferrule holding recess; wherein when a fiber optic ferrule is received in the ferrule holding recess the attachment arm biases the fiber optic ferrule toward the disk polishing surface.
 2. The device of claim 1, wherein the ferrule holder has a water injecting recess positioned substantially adjacent to the ferrule holding recess.
 3. The device of claim 2, wherein the water injecting recess is positioned toward the disk center and the ferrule holding recess is positioned toward the disk outer periphery.
 4. The device of claim 1, further comprising a shroud encompassing the disk and the polishing surface.
 5. The device of claim 1, wherein the attachment arm has a first arm mount and a second arm mount attached substantially perpendicular to the ferrule holder and having a spring extending therebetween.
 6. The device of claim 1, wherein the attachment arm has a cable receiving recess for receipt of a fiber optic cable extending from the fiber optic ferrule positioned in the ferrule holding recess.
 7. The device of claim 1, further comprising a mounting plate for mounting the ferrule holder a predetermined distance from the polishing surface.
 8. The device of claim 1, further comprising a holding plate having a ferrule end face receiving recess having a smaller diameter than the ferrule holding recess and positioned adjacent to the ferrule holding recess and polishing surface.
 9. The device of claim 1, wherein the abrasive is a diamond grit.
 10. The device of claim 1, wherein the abrasive is a ceramic material.
 11. The device of claim 1 wherein the abrasive is a carborundum material.
 12. A fiber optic ferrule polishing devise comprising: a disk having an outer periphery and a center; a plurality of rings having a polishing surface coated with varying degrees of abrasive and an attachment surface attached to the disk such that the courseness of abrasive on the rings decreases from the outer periphery to the center; a ferrule holder having a ferrule holding recess substantially adjacent to the polishing surface, a water injecting recess substantially adjacent to the ferrule holding recess and an attachment arm pivotally attached to the ferrule holder such that the arm is positioned substantially adjacent to the ferrule holding recess; and wherein when a fiber optic ferrule is received in the ferrule holding recess the attachment arm biases the fiber optic ferrule toward the disk polishing surface.
 13. The device of claim 12, wherein the water injecting recess is positioned toward the disk center and the ferrule holding recess is positioned toward the disk outer periphery.
 14. The device of claim 12, further comprising a shroud encompassing the disk and the polishing surface.
 15. The device of claim 12, wherein the attachment arm has a first arm mount and a second arm mount attached substantially perpendicular to the ferrule holder and having a spring extending therebetween.
 16. The device of claim 12, wherein the attachment arm has a cable receiving recess for receipt of a fiber optic cable extending from the fiber optic ferrule positioned in the ferrule holding recess.
 17. The device of claim 12, further comprising a mounting plate for mounting the ferrule holder a predetermined distance from the polishing surface.
 18. The device of claim 12, further comprising a holding plate having a ferrule end face receiving recess having a smaller diameter than the ferrule holding recess and positioned adjacent to the ferrule holding recess and polishing surface.
 19. The device of claim 12, wherein the abrasive is a diamond grit.
 20. The device of claim 12, wherein the abrasive is a ceramic material.
 21. The device of claim 12 wherein the abrasive is a carborundum material.
 22. A fiber optic ferrule polishing devise comprising: a disk having an outer periphery and a center; a plurality of rings having a polishing surface coated with varying degrees of abrasive and an attachment surface attached to the disk such that the courseness of abrasive on the rings decreases from the outer periphery to the center; a ferrule holder having a ferrule holding recess substantially adjacent to the polishing surface, a water injecting recess substantially adjacent to the ferrule holding recess and an attachment arm pivotally attached to the ferrule holder such that the arm is positioned substantially adjacent to the ferrule holding recess; a holding plate having a ferrule end face receiving recess having a smaller diameter than the ferrule holding recess and positioned adjacent to the ferrule holding recess and polishing surface; a mounting plate for mounting the ferrule holder a predetermined distance from the polishing surface; and wherein when a fiber optic ferrule is received in the ferrule holding recess the attachment arm biases the fiber optic ferrule toward the disk polishing surface.
 23. The device of claim 22, wherein the water injecting recess is positioned toward the disk center and the ferrule holding recess is positioned toward the disk outer periphery.
 24. The device of claim 22, further comprising a shroud encompassing the disk and the polishing surface.
 25. The device of claim 22, wherein the attachment arm has a first arm mount and a second arm mount attached substantially perpendicular to the ferrule holder and having a spring extending therebetween.
 26. The device of claim 22, where in the attachment arm has a cable receiving recess for receipt of a fiber optic cable extending from the fiber optic ferrule positioned in the ferrule holding recess.
 27. The device of claim 22, wherein the abrasive is a diamond grit.
 28. The device of claim 22, wherein the abrasive is a ceramic material.
 29. The device of claim 22 wherein the abrasive is a carborundum material. 